Polaritons under Extensive Disordered Gas-Phase Molecular Rotations in a Fabry–Pérot Cavity

Abstract

Directly simulating a large number of molecules interacting with cavity modes is important to understand the polariton chemistry. However, such a task is challenging due to the steep scaling of the computational cost as a function of the number of molecules. Here, we simulate the dynamics and spectra of 1 million gas-phase molecules in a Fabry−Peŕot cavity, each weakly interacting with light. We emphasize the effects of molecular rotations and disorder on the polariton dynamics and spectra. Our calculations reveal the existence of the collective effects in the spectra despite the disorder and rotations. Increasing rotational frequencies leads to larger Rabi splitting between lower and upper polaritons, whereas random rotational phases reduce this splitting. These findings await validation in gas-phase polariton experiments.